Abstract:By ultrastructural studies on the secreting activities of pearl-sac cells of Hyriopsis cumingii , the pearl-sac epithelial cells have developed rough endoplasmic reticulum for synthesizing was found . Some kinds of substance which are mainly composed of proteins , sulfated mucopolysaccharides and neutral mucopolycaccharides , and the synthesized substance can be secreted by ways of mivrovilli , lump-like substance , cell gap , large grain , and the gland cells between the pearl-sac epithelial cells , which are from the connective tissue of the mantle and contain rich neutral mucopolysaccharides , and can secrete their contents by means of the breaking of the top of these cells . The secretion diversity of the pearl-sac epithelial cells is determined by the complexity of the pearl composition .The secretion of the pearl-sac cells is rhythmic , which is adaptive for the formation of the multiple crystalline layers of the pearl .

Abstract:Comparative study of ultrastructure of oocytes and various organellae was conducted on diploidy and triploidy oyster , Crassostrea gigas , during their oocyte development by means of electronic microscope .The results indicated that , during the period of vitellogenesis , oocytes of diploidy oyster were oval-shaped with developed organellae and numerous yolk granellae evenly distributed in cytoplasm .Microvilli circled round oocytes .Biosynthesis and metabolism activated inside .In contrast , most oocytes of triploids were in oblong or irregular shape , with a small amount of organellae and fewer yolk granules , the latter in some oocytes was even deformed .No microvilli were observed outside oocytes .Weak biosynthesis and metabolism occurred .Hindered oogenesis of triploid oyster revealed that development of their oocytes was blocked in vitellogenesis phase .

Abstract:In the present paper , the conditions for the induction of interferon from grass carp , Ctenopharyngodon idellus were described .The results showed that the interferon of grass carp could be induced rapidly following experimental infection with the viruses .After the virus being inoculated for 24 hours , the interferon activity in serum sample exhibited obviously .Maximum yields of serum interferon were observed after the virus being inoculated for 3 days .The production of grass carp interferon was influenced by the environmental temperature , different viral inducers , virus dosages as well as the nutrient conditions of the fish .The induction of grass carp interferon was shown to be temperature-dependant .Titers of interferon induced at 25 ℃ was higher than that at 15 ℃ and 8 ℃. Among seven viral inducers , the interferon inducing ability of six RNA viruses was higher than that of DNA virus .And the GCHV which was of the genome of dsRNA possessed the highest interferoninducing ability .High virus dosages and good nutrient conditions for the fish were advantageous to the production of interferon .The production of grass carp interferon could also be enhanced by priming the fish with interferon or pre-inducing the fish with inactivated GCHV for appropriate time .However , the influence of virus infectious activity and the ages of fish on the induction of interferon had not been observed .

Abstract:From 1996 to 1997 , experiments were carried out to induce triploid in the Pacific oyster (Crassostrea gigas ) by inhibiting release of polar body I of the zygotes with 6- dimethylaminopurine (6-DMAP).L16(4 5)design was selected to engage in orthogonal experiment of three factors and four levels :the four levels of 6-DMAP concentration were 150 , 300 , 450 and 600 μmol/L , respectively ;the induced occasion (the time after sperms and eggs confused)was 10 , 15 , 20 and 25 min , respectively ;and the induced duration was 10 , 15 , 20 and 25 min , respectively . Experiments were repeated twice .The highest induced ratio was (71 .3 ±1 .2)%, the embryonic hatching ratio of this experiment group was (55 .5 +3 .1)%, and the abnormality of D-shape larvae was (10 .7 ±1 .6)%.The results calculated by direct analysis indicated that the best level combination of inducing factors for triploid in Pacific oyster was 25 -25 .5 ℃water temperature , at 10 min after sperms and eggs confused and the fertilized eggs were rinsed continuously in sea water with 600 μmol/ L 6-DMAP, the treatment duration is 15 min .The sequence of three factors for deciding triploid was : 6-DMAP concentration ※ induced occasion ※ induced duration .The influence of the factor 6-DMAP concentration on the triploid was very obvious , but the influences of the factors induced occasion and induced duration were not obvious .

Abstract:The paper reported that the growth and reproduction of Dicrateria sp. were obviously, inhibited by monocrotophos. With the prolonging time of stress, peroxidase( POD) activity decreased, active oxygens accumulated remarkably in the cell, malondialdehyda( MDA) content and membrane permeability increased synchronously. On the contrary, the activity of superoxide dismutase (SOD) changed irregularly during the whole time of stress. The results showed that act ive oxygens resulted in cellular damage by means of lipid peroxidation, and compared w ith SOD, POD played more important role on scavenging of active oxygens.

Abstract:The result of enclosure experiment carried out from summer to autumn in 1995 and 1996 .It showed that during feeding period the gross primary production of phytoplankton (PPGP)was lower and respiration of water column (WR)relatively higher , in most enclosures PPGP/WR <1 , the PPGP in enclosures polycultured shrimps and a hybrid tilapia was higher , in opposite , the enclosure polycultured shrimps , tilapia and Ruditapes Philippinarum had the lowest PPGP.When suitable fertilization was adopted on the basis of daily feeding , PPGP in experimental enclosures was significantly higher than that as only feeding was adopted , PPGP/WR >1 , but there was not apparent difference in PPGP between enclosure monocultured shrimps , polycultured shrimps and tilapia , polycultured shrimps and bay scallop , and polycultured shrimps and Sinonvacula constricta .These results indicate that the cultural management measures , routine feeding and fertilization , stocked tilapia and bivalve and periphery algae all affect the gross primary production in enclosures , in which management measures usually play an important role .

Abstract:The carbon budget of Chinese Prawn(Penaeus chinensis)fed with polychaete worm (Neanthes japonnica) under different salinity and fed with different diets (polychaete worm and formulated diet)under salinity of 31 was studied .The experimental results showed that the salinity ranging from 5 -35 and the temperature at 25 ℃, the maximum carbon intake was 61 .64(mg·g -1· d -1)at salinity of 13 , but the suitable salinty for growth is 20 , and carbon conversion efficiency was highest of 25 .84 %, the best specific growth rate from carbon is 3 .89 %.The mechanism of salinity effect on carbon growth of the prawn was decided by food intake and carbon conversion efficiency .The growth of Chinese prawn fed with polychaete worm was significantly larger than that fed with formulated diet .Their carbon conversion efficiency was 26 .80 % and 13 .78 % of carbon intake respectively .The mechanism of food effect on carbon growth was decided by assimilation ratio and conversion efficiency .

Abstract:The reproductive habit , season and reproduct ive capacity , hatching, development and metamorphosis of larva, and development course of naiad and young Rapana venosa were studied in this paper. It s reproductive period is from June to August ( 19- 26 e ) every year in inshore of Shandong . The parents mate many times in a reproductive period. The female spawns 2. 1 times and lays 655. 9 egg bags in average every reproductive period. The individual reproductive capacity is 754 thousants in average. There are average 1149 zygotes in a egg bag. Under 21- 22 e , the religer larva hatched af ter 20- 26 days. Hatching rate is 80. 8% . After 26- 30 days, the larva developed into naiad and grew into young snail after 57 days.

Abstract:Through the improvement of both the ways of preparation and the methods of application , better effects of the immobilized PSB on the purification of water quality were achieved . Four kinds of immobilized carrier were tested .The results showed that the calcium alginate gel pellets containing 3 % permutite was better than others in the aspects of both pellet strength and the activity of purifying water quality .The decrease of NH3 -N ,NO2 -N concentration and the value of COD in the water varied in step with the increase of the embedding-ratio .The proper dosage of the immobilized PSB and the methods of activating immobilized PSB were studied .The experiments in production scale was carried out in 50m 3 zoeae rearing ponds .The highest zoeae survival rate of 40 .6 %was found in the pond where 19kg of immobilized PSB were added .Compared to the pond where free PSB were added in the same dosage , the zoeae survival rate was increased by 11 .2 %.Thus , the harvest of megalopa increased by 157 .5 thousands pieces of larvae per pond .

Abstract:The effects of the feed with different amount of the dried Spirulina platensis and fresh Spirulina platension on the growth and body color changes in Crucian carp have been studied. The result shows that the more the amount of Spirulina platensis in feed is, the longer and weightier the f ish will be, and the brighter the body color of the fish will become. Feeding with fresh Spirulina platensis would make a better ef fect on increasing fish color and body weight than feeding with the Spirulina pander feed. The methods of quant itative measuring body color have also been studied. When the amount of Spirulina platensis in feed increased, black pigment cells and the OD value of the red pigment abstract with acetone in the f ish scale are promoted. So it is realistic to count the black pigment cells and to analyse the OD value of the red pigment for distinguishing the fish color grades.

Abstract:The lymphatic organ of shrimp Penaeus chinensis and the cultured lymphatic tissues fromfarmed and wild shrimps were examined under the transmission electronic microscope (TEM). The particles with envelope , which are icosahedron in shape and 136 nm in diameter , were found in the cytoplasm in all samples .It seemed to be the Iridovirus .Another virus was found in the cytoplasm of lymphatic tissue of farmed shrimp .The particles were icosahedron , 33 nm in diameter and without envelope , which seemed to be the Picornavirus .No significant replication of the viruses was found in the cultured cells .Pathological changes , including karyorrhexis , nuclear hypertrophy , cytoplasm vacuolization , tissues necrosis of lymphatic organ were also observed .

Abstract:Two strains of 97-7-2C and 97-9-2A. were isolated from the liver of the diseased Trionyx sinense of Taiwan polulat ion. After artificial infection by these two strains, the diseased rate and mortality rate were all 100% , in the young turtles of 10 ~ 15g body weight. Through the cultivation and physica-l biochemical reactive determination, 97-7-2C was identif ied as Yersinia enterocolitica, 97-9-2A. was identified as Y. pseudotuberculosis. They can cause septicemia in turtles. The alterat ive pathological changes were happened signif icantly in liver, kidney and intestine signif icant ly , but most seriously in intestine. The results from 20 drug selection testings indicated that , the Y. enterocolitica is sensitive to gentamycin, and trimethoprim, Y. pseudotuberculosis is sentive to trimethoprim and furantoin.

Abstract:The maximum sustainable yield( MSY) , fishing effort for MSY ( fM SY ) , maximum economic yield ( MEY ) , f ishing ef fort for MEY( fMEY ) and the maximum economic revenue of the southern Fujian coastal fishery were est imated by Schaefer and Fox surplus production models and the bio-economic models derived from these two models. The management model for this f ishery was established. The economic revenue from the f ishery managed w ith maximum yield and maximum revenue as the target was compared. At last, management with maximum yield was recommended for this f ishery in the near furtune.

Abstract:Experiments showed that the 50 % retention length (L0.5)increased with the meshsize of cod-end .When the mesh-size of cod-end increased from 40mm to 50mm with 5mm intervals , 50 % retention lengths (L0 .5)were 85 .88 , 90 .26 , 95 .32mm for Parapenaeopsis hardwickii , 87 .58 , 88 .09 , 92 .56mm for Solenocera crassicornis and 85 .04 , 85 .96 , 88 .32mm for Trachypenaeus curvirostris respectively .The relations between the mesh-size of the cod-end and 50 % retention length of the three species mentioned above can be described as follows : P .hardwickii L0.5 =48 .03 +0 .940Me , S .crassicornis L0.5 =67 .00 0 .498Me , T .curvirostris L0.5 =71 .68 0 .328Me , Mixed up three species : L0.5 =60 .59 0 .636Me , It is necessary to increase the mesh-size of cod-end from the range of 20mm～ 30mm to the range of 35 ～ 40mm in fishing operation .As at the latter range of mesh-size , 50 %retention length (L0.5)for P .hardwickii , S .crassicornis and T .curvirostris were 80.93 ～ 85.63mm、84.43～ 86 .92mm and 83 .16 ～ 84.8mm respectively , and 82 .85 ～ 86 .03mm If the three main shrimp species were mixed up .It will help to release juvenile shrimps and fish and in the meanwhile improve the size and quality of shrimp catch .

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